Methods, apparatus, and devices for noise reduction

• US 20060262147A1
• Filed: 05/23/2005
• Published: 11/23/2006
• Est. Priority Date: 05/17/2005
• Status: Active Grant

• Current Assignee: Barco NV
• Original Assignee: Barco NV
• Inventors: Kimpe, Tom, Matthijs, Paul
• Granted Patent: US 7,639,849 B2
• Time in Patent Office: Days
• US Class Current: 345/690
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/029 by monitoring one or more pixels in the display panel, e.g. by monitoring a fixed reference pixel
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2360/145 the light originating from the display screen
• CPC Class Codes: G09G 3/20 for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters

Abstract

Embodiments include applying a compensation to an image signal based on nonuniformity of a display device. The compensation is based on information about variations in light-output response among elements of the display device. The compensation is also modified based on a characteristic of a desired use of the display.

Claims

1. A method of image processing, said method comprising:

for each of a plurality of pixels of a display, obtaining a measure of a light-output response of at least a portion of the pixel at each of a plurality of driving levels;

to increase a visibility of a characteristic of a displayed image during a use of the display, modifying a map that is based on the obtained measures; and

based on the modified map and an image signal, obtaining a display signal.

2. The method of image processing according to claim 1, wherein the map comprises at least one of a luminance map of the display and a chrominance map of the display.

3. The method of image processing according to claim 1, wherein said modifying a map is based on a characteristic of a feature to be detected during display of an image.

4. The method of image processing according to claim 1, wherein said modifying a map is based on a characteristic of a class of images to be displayed.

5. The method of image processing according to claim 1, wherein said modifying a map to increase a visibility of a characteristic of a displayed image includes:

obtaining a characteristic of an image to be displayed; and

modifying the map according to the obtained characteristic.

6. The method of image processing according to claim 1, wherein said modifying a map includes modifying the map according to a desired frequency response of the display.

7. The method of image processing according to claim 1, wherein said modifying a map includes modifying the map according to a desired response of the display to a predetermined image characteristic.

8. The method of image processing according to claim 1, wherein said modifying a map includes attenuating a magnitude of a first component of the map relative to a magnitude of a second component of the map, wherein the second component has a higher spatial frequency than the first component.

9. The method of image processing according to claim 8, wherein said modifying a map includes attenuating a magnitude of a third component of the map relative to the magnitude of the second component of the map, wherein the third component has a higher spatial frequency than the second component.

10. The method of image processing according to claim 1, wherein said modifying a map to increase a visibility of a characteristic of a displayed image includes modifying the map to increase a visibility of an image area having a spatial frequency greater than 0.1 cycles per degree.

11. The method of image processing according to claim 1, wherein said modifying a map to increase a visibility of a characteristic of a displayed image includes modifying the map to increase a perceptibility of features of a displayed image that are mutually separated by more than one arc-minute.

12. The method of image processing according to claim 1, wherein said modifying a map to increase a visibility of a characteristic of a displayed image includes modifying the map to increase a visibility of an area in accordance with a contrast of the area.

13. The method of image processing according to claim 1, wherein said modifying a map to increase a visibility of a characteristic of a displayed image includes modifying the map according to a contrast sensitivity function.

14. The method of image processing according to claim 1, wherein said modifying a map to increase a visibility of a characteristic of a displayed image includes modifying the map according to a predetermined feature of interest.

15. The method of image processing according to claim 1, wherein said modifying a map to increase a visibility of a characteristic of a displayed image includes modifying the map to increase a visibility of a clinically relevant feature.

16. The method of image processing according to claim 1, wherein said modifying a map to increase a visibility of a characteristic of a displayed image includes modifying the map according to a shape and size of a clinically relevant feature.

17. The method of image processing according to claim 1, wherein said modifying a map to increase a visibility of a characteristic of a displayed image includes modifying the map to increase a visibility of rounded shapes.

18. The method of image processing according to claim 1, wherein the image signal is derived from a photographic representation of living tissue obtained using at least one among a penetrating radiation and a penetrating emission.

19. The method of image processing according to claim 1, wherein the image signal is derived from an X-ray photograph.

20. The method of image processing according to claim 1, said method comprising verifying that a desired structure was not removed from the map during said modifying.

21. The method of image processing according to claim 20, wherein said verifying includes calculating a difference between the map and the modified map.

22. The method of image processing according to claim 1, wherein said modifying a map to increase a visibility of a characteristic of a displayed image includes modifying the map according to a first selected characteristic in a first region of the display, and modifying the map according to a second selected characteristic in a second region of the display,

wherein the first characteristic is different than the second characteristic, and wherein the first region is separate from the second region.

23. The method of image processing according to claim 1, said method comprising calculating a plurality of correction functions based on the modified map.

24. The method of image processing according to claim 23, wherein said obtaining a display signal comprises applying, to a value of the image signal that corresponds to a pixel of the display, a correction function that corresponds to the pixel from among the plurality of correction functions.

25. The method of image processing according to claim 1, wherein the map comprises a plurality of correction functions, each of the plurality of correction functions corresponding to at least one of the plurality of pixels.

26. The method of image processing according to claim 25, wherein said obtaining a display signal comprises applying, to a value of the image signal that corresponds to a pixel of the display, a correction function that corresponds to the pixel from among the plurality of correction functions.

27. The method of image processing according to claim 1, wherein the luminance resolution of the display signal is greater than the luminance resolution of the image signal.

28. The method of image processing according to claim 1, wherein the luminance resolution of the display signal is greater than the luminance resolution of the display.

29. The method of image processing according to claim 28, said method comprising displaying the display signal on the display, said displaying including performing an error diffusion technique based on the display signal.

30. The method of image processing according to claim 1, said method comprising attenuating a component of the image signal according to a characterization of noise of an image detector.

31. The method of image processing according to claim 1, wherein said modifying a map includes modifying the map to reduce a visibility of a defective pixel of the display.

32. A data storage medium having machine-readable instructions describing the method of image processing according to claim 1.

33. An image processing apparatus comprising:

an array of storage elements configured to store, for each of a plurality of pixels of a display, a measure of a light-output response of at least a portion of the pixel at each of a plurality of driving levels; and

an array of logic elements configured to modify a map based on the stored measures and to obtain a display signal based on the modified map and an image signal,

wherein the array of logic elements is configured to modify the map to increase a visibility of a characteristic of a displayed image during a use of the display.

34. The image processing apparatus according to claim 33, wherein said array of logic elements is configured to attenuate a magnitude of a first component of the map relative to a magnitude of a second component of the map, wherein the second component has a higher spatial frequency than the first component.

35. A method of image processing, said method comprising:

for each of a plurality of pixels of a display, obtaining a measure of a light-output response of at least a portion of the pixel at each of a plurality of driving levels;

modifying a map of the display that is based on the obtained measures, said modifying including, with respect to a magnitude of a component having a spatial period between one and fifty millimeters, decreasing a magnitude of a component having a spatial period less than one millimeter and decreasing a magnitude of a component having a spatial period greater than fifty millimeters; and

based on the modified map and an image signal, obtaining a display signal.